For those who lived through it, it’s hard to find words not already expressed about the assassination of President John F. Kennedy, which shook this nation to its core 53 years ago this week.

If you were alive in 1963, even as a child, you probably remember the day. You remember who told you. Where you were. How people around you reacted. And that sinking feeling in the pit of your stomach, a new unease created by an event you thought never could happen again in America.

Sometimes it takes years to see how seminal events like this change us. That’s the case with the Sept. 11, 2001 terrorist attacks on the World Trade Center, whose effects are still playing out daily. Wars still rage as a direct or indirect consequence, and the politics that brought first Barack Obama and now Donald Trump to the presidency are grounded in what happened that day. It is a story unfinished.

Few of us were alive when the Japanese bombed Pearl Harbor on Dec. 7, 1941, another of those touchstones of horror. But the Baby Boomers, born soon after, were acutely aware of how the shock shaped their families’ lives. They were what journalist Tom Brokaw deemed the Greatest Generation, raised during the Great Depression and galvanized with the strength and patriotism to win World War II.

Then, 22 years later came that gruesome 1963 day when the youthful John Kennedy became the fourth U.S. president to be assassinated, joining Abraham Lincoln, James Garfield and William McKinley.

It shook the nation to its core. It was the first assassination in 62 years and the only one recorded on film. Nearly every American saw the clips.

Kennedy’s assassination has been said to represent the nation’s collective loss of innocence. But that’s oversimplified. While his presidency was indeed idealistic, optimistic and glamorous, the times were anything but innocent.

Just a year earlier, Kennedy had taken the nation to the brink of nuclear war with the Soviet Union in the Cuban missile crisis. The year before that, he had presided over the disastrous CIA-backed Bay of Pigs invasion designed to overthrow Fidel Castro, who, by the way, is still there. And by 1963, his administration had already escalated the U.S. presence in South Vietnam to 16,000 troops, up from the 900 advisers the Eisenhower administration had committed.

Meanwhile, as the long-simmering civil rights movement gathered steam in that era, television news cameras captured nonviolent marchers and protesters being met with water cannons and police nightsticks.

Hardly innocent. But perhaps Kennedy’s killing was all the more devastating because we needed the optimism he seemed to bring.

Still, we survived. Our spirit survived.

Today many Americans are shaken by the results of this month’s election, fearing a new president who may present a danger to the values and perhaps even to people we hold dear. It may be helpful to invoke that wellspring of inner strength to move on.